Card cover sheet aperturing apparatus

ABSTRACT

1. In apparatus of the character described, a cutter assembly having a support; four cutting knives mounted on said support in a rectangular pattern and with respect to a common plane on said support with each knife having a cutting edge inclined with respect to said plane and with adjacent ends of adjacent knives extending unequal distances from said plane; an apertured plate slidably mounted on said support to a position extending forwardly of and surrounding said knives; and spring means acting between said plate and said support normally urging said plate to said position.

111mm Mates Patent [191' Dedona et a1.

14 1 *May 29, 1973 1 1 CARD COVER SHEET APERTURING APPARATUS 175] Inventors: Francis A. Dedona, Sherman Oaks; James W. Lucas, Los Angeles, both of Calif.

[73] Assignee: Scionics Businesss Products, Inc.,

Rochester, NY.

[ Notice: The portion of the term of this patent subsequent to May 29, 1986, has been disclaimed.

[22] Filed: Aug. 26, 1965 21 App1.No.: 482,881

Related U.S. Application Data [63] Continuation-impart of Ser. No. 274,025, April 18,

1963, Pat. No. 3,248,986.

[52] US. Cl. ..83/l40, 83/98, 83/125, 83/620, 83/689 [51] int. Cl. ..B26f 11/44 [58] Field of Search ..83/620, 622, 688, 83/689, 140, 98, 125

[56] References Cited UNITED STATES PATENTS 1,322,876 11/1919 Cameron ..83/689 1,416,800 5/1922 Detjcn "83/620 1,519,983 12/ 1924 Robbins 83/622 2,201), 1 23 5/1940 Rocdclls r i ..83/14() 2,255,846 9/1941 Grammcr ..83/582 2,329,061 9/1943 Kopczynskium v.83/140 2,466,291 4/1949 Williams ..8 3/140 3,130,885 4/1964 Fleming ..83/689 FOREIGN PATENTS OR APPLICATIONS 856,084 5/1940 France ..83/689 1,107,189 11/1959 Germany ..83/622 Primary Examinerlames M. Meister Attorney-Homer 0. Blair, Robert 1.. Nathons and William C. Roch EXEMPLARY CLAIM 1. In apparatus of the character described, a cutter assembly having a support; four cutting knives mounted on said support in a rectangular pattern and with respect to a common plane on said support with each knife having a cutting edge inclined with respect to said plane and with adjacent ends of adjacent knives extending unequal distances from said plane; an apertured plate slidably mounted on said support to a position extending forwardly of and surrounding said knives; and spring means acting between said plate and said support normally urging said plate to said position.

3 Claims, 24 Drawing Figures PATENIEUMAY29 I975 SHEET 3 BF 4 INVENTORj, K) Fem/05 4 000/144 Q Q w JAMES [4/ (v5.45

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CARD COVER SHEET APElRTURING APPARATUS The present application is a continuation-in-part of our application Ser. No. 274,025 filed Apr. 18, 1963,

now US. Pat. No. 3,248,986, granted May 3, 1966,

The present invention relates to an aperturing machine which is particularly useful in providing an apertured portion in a cover sheet which overlies an apertured portion in an electric machine accounting business type card so that it may be used, for example, in mounting film on such apertured cover sheet and within the apertured portion of the card.

Briefly, the machine described herein is provided to receive a card with a cover sheet over an apertured portion of the card in an indexed position with respect to a stationary rectangular cutting element ready for aperturing of the cover sheet by a rectilinearly movable cooperating cutter assembly having four shear elements. The cutter assembly, slidably mounted in a guide is moved by a lever having one end pin connected to the cutter assembly, its other end pivoted on a stationary frame and an operating mechanism pin connected to an intermediate portion of the lever. This mechanism involves a rod having one end pin connected to such intermediate portion and having two rollers thereon each cooperating with a separate cam on a motor driven shaft that rotates about a fixed axis and extends transversely through the rod with the rod being slidably mounted on the shaft. A coil compression spring has one of its ends seated on the other end of the rod with the other end of the spring pressing one of the rollers, which is slidable on the rod, into engagement with one of such cams so that rotation of such one cam causes energy to be stored in the spring.

This stored energy in the spring is released when the other roller, which rotates about an axis fixed on the rod, enters an indented portion of the other cam such that the cover sheet is apertured by this previously stored energy. When and as such other roller starts to move out of such indented portion, such one cam allows said one roller to move as required to hold the spring length approximately constant during retraction of such other cam that effects the positioning of the cutter assembly. In other words, such one cam member affects essentially the compression of the spring and such other cam affects essentially the positioning of the cutter assembly and functions to allow energy stored in the spring by such one cam to be released for the cover sheet aperturing operation during which initially a spring urged frame on the cutter is pressed against the card and then, when so pressed against a stationary frame, the cover sheet is apertured by the moving cutter assembly.

it is therefore a general object of the present invention to provide an improved machine of the character described.

A specific object of the present invention is to provide a cam operated cutting machine in which there is little, if any, load on the cutter positioning cam during the cutting operation.

Another specific object of the present invention is to provide a machine of this character which incorporates Another specific object of the present invention is to provide a machine of this character which is relatively small, rugged and drivable with relatively small peak power so that a relatively small motor may be used as a prime mover.

Another specific object of the present invention is to provide a machine of this character which is adaptable either for manual, or motor, or solenoid operation.

Another specific object of the present invention is to provide a machine of this character using a cutter which progressively cuts through a thin cover sheet material to allow the stored spring energy to be released uniformly during a relatively long travel of the cutter.

Another specific object of the present invention is to provide an improved bearing structure for a reciprocable cutter assembly.

Another specific object of the present invention is to provide an improved actuating system for a reciprocable cutter.

Another specific object of the present invention is to provide a machine of this character in which means are automatically operated for clearing the machine of the cut out portion of the cover sheet.

Another specific object of the present invention is to provide a machine of this character in which a single switch is used to effect energization of the machine and to effect a de-energization of the machine automatically after a predetermined angular rotation of a shaft.

Anotherspecific object of the present invention is to provide an arrangement of this character capable of cutting extremely thin film non-metallic materials which have very high tear strength such as for example Mylar which has a tendency to deform or stretch rather than to shear evenly.

Another specific object of the present invention is to provide a cutting arrangement which is essentially selfsharpening.

Another specific object of the present invention is to provide an arrangement of this character into which one or more cards may be inserted so that the operating speed advantages of multiple card aperturing during a single operating cycle may be realized.

Another specific object of the present invention is to provide a machine of this character in which there is no rigid mechanical connection between the cutting element, the driving mechanism and energy source such that neither the cutting element, mechanism nor driving motor can be damaged by an inadvertent overloading of the punch member.

Another specific object of the present invention is to provide an arrangement of this character involving an energy storage system wherein rapid linear reciprocationis accomplished in a small fraction of the total operating cycle, the larger fraction of the remainder of the cycle being used for the restoring of energy.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof,'may be best understood by references to the following description taken in connection with the accompanying drawings, in which:

FIG. l is an irregular sectional view taken in the direction indicated by arrows 1-1 in'FllG. 2.

FIG. 2 is a sectional view taken as indicated generally by the arrows 2-2 in FIG. 1 and illustrates-the cutter assembly in a retracted position, a portion of the switch operating mechanism illustrated in FIG. 4 being omitted.

FIG. 3 is a sectional view indicated generally by the arrows 3-3 in FIG. 5 corresponding to a condition wherein the cutter assembly is in an advanced position.

FIG. 4 illustrates the switch and operating mechanism therefor.

FIG. 5 is a sectional view taken substantially as indicated by arrows 5-5 in FIG. 2.

FIG. 6 is a sectional view taken substantially as indicated by arrows 6-6 in FIG. 2.

FIG. 7 is a view taken generally as indicated by 7-717 in FIG. 5 corresponding to the condition when the cutter is in its most advanced position.

FIG. 8 is a perspective view illustrating a portion of the apertured frame member.

FIG. 9 is a sectional view taken substantially as indicated by arrows 9-9 in FIG. 1.

FIG. 10 is a perspective view showing a stationary bearing member for the movable cutter assembly.

FIG. 11 is a perspective view of a bearing member support for the movable assembly with the spring urged bearing member removed.

FIG. 12 is a view taken substantially as indicated by the arrows 12-12 in FIG. 1.

FIG. 13 is a perspective view of the movable cutter assembly.

FIG. 14 is a perspective view of the spring urged card engaging frame.

FIG. 15 is a perspective view of the frame mountable on the movable cutter assembly.

FIGS. 16 and 17 illustrate the position of the spring stressing cam and the cutter positioning cam respectively, each corresponding to the retracted position of the cutter, i.e., cocked position wherein maximum energy is stored in the spring.

FIGS. 18-24 illustrate modified forms of apparatus embodying the present invention, FIG. 18 being a view taken substantially in the same direction as in FIG. 1, FIG. 19 being a view taken substantially in the same direction as FIG. 6, FIG. 20 being a view taken substantially as indicated by lines 20-20 in FIG. 18, FIG. 21 illustrating the front of the modified cutting element, FIGS. 22 and 23 being views taken substantially on corresponding lines 2222 and 23-23 in FIG. 21, and FIG. 24 being a view in enlarged form taken substantially on line 24-24 of FIG. 23.

The apparatus described has a supporting frame which includes base plate 20 with two parallel spaced vertical side plates 11, 12 secured thereto and extending upwardly therefrom, these plates being secured by screws 13. Between the upper ends of side plates 11, 12

member 22 being secured to the side plate 11 by bolts 25 and to frame plate 15 by screws 26 and similarly the bracket member 23 is secured to the side plate 12 by bolts 27 and to the frame plate 15 by screws 28.

Also mounted between the upper ends of the side plates 11, 12 and secured thereto by dowel pins 20A or other securing means is a rectangular apertured die plate 30 having the apertured portion 32 defined by outwardly tapered walls as seen in FIGS. 2 and 6 with the entrance to such apertured portion being defined by a hardened rectangularly apertured paper cutting plate 34 recessed and secured within plate 30. This plate 30 as seen in FIG. 2 has an upper rounded edge portion 36 to facilitate the introduction of a card and a shouldered portion 38 acting as a stop for the introduced card and also as a partial support for the card.

To provide additional support for the introduced card, there is provided a card supporting structure that includes a horizontally extending bar 40 with an upper tapered lip portion 41 and a plate 43 having a right angle bent portion 44 secured to the frame side plate 11 by screws 46, the bar 40 being secured to this plate 43 by screws 47; and as a prolongation of the plate shouldered portion 38 the frame side plate 11 has an open ended slotted portion 49 allowing introduction of the card so that the bottom edge of the card may rest on such shouldered portion 38 and the card ledge or bar 40 with a portion of the card leaning against plate 43 and contacting the stop element 42 so that the card is indexed with respect to the stationary cutting element 34, the stop element 42 being secured to the frame plate 15 by screws 42A as shown in FIG. 6.

Cutting or punching of the card occurs between the hardened stationary rectangular insert 34 and a rectilinearly movable punch or cutter assembly 50 which is moved by lever 52 having its upper end pin connected to assembly 50 and its lower end pivotally mounted in bearing assembly 54 mounted on base frame plate 10, the lever 52 being actuated at a point intermediate its ends by a mechanism described later.

The cutter assembly 50 as seen in FIG. 13 includes four cutting elements 55, 56, 57 and 58 secured in interlocking relationship by screws 60 to a plate 62 which, in turn, is secured by screws 63 to the front face of the support block 64 with the rearwardly located straight edges of the cutting elements bearing on a peripheral recessed portion of plate 62 as illustrated in FIG. 6 and with the forwardly located cutting edges of the cutting elements being inclined with respect to the plane of such plate 62 such that adjacent ends of adjacent cutting edges are separated different distances from such plane, the smaller end of one cutting element being adjacent to the larger end of the adjacent cutting element whereby each cutting element acts as a scissors element with respect to a corresponding edge of the hardened insert plate 34 (FIG. 2). As shown, the support block 64 has a slotted portion 66 for accommodating the end of lever 52 and a hole 67 extending therethrough for receiving a pivot pin 69 (FIG. 2) engaged by an open ended slotted portion 71 in'lever 52. Also as seen in FIG. 13 the support 64 has a longitudinally extending bevelled surface 70.

The cutter assembly 50 also includes an air nozzle 62A threaded in plate 62, the nozzle 62A being in communication with an angled passageway 628 (FIG. 6) having a fitting 62C threaded therein for attachment to one end ofa flexible hose 62C having its other end connected to the outlet side of an air pump 62D (FIG. 1) which is operated after a cutting operation to produce a blast of air from nozzle 62A to clear the machine of that rectangular portion cut out of the cover sheet.

This cutter assembly 50 is slidably mounted using the previously mentioned bevelled surface 70 on cutter block 64 as a bearing surface and against which pressure, developed by springs, is applied to urge the assembly 50 against the raised bearing surfaces 73 and 74 (FIG. respectively, on replaceable bearing blocks 81and 83 mounted on corresponding interior sides 75 and 76 of L-shaped bearing block 77 integrally formed with a plate portion 78 for mounting on the apertured frame plate by screws 79. This bevelled surface 70 on cutter assembly 50 is engaged by a bearing plate 80 (FIG. 9) slidably recessed within an apertured portion 82 in the bearing support 84 and urged outwardly by coil compression springs 86, the bearing support 84 being secured to the apertured frame plate 15 by screws 88. For lubrication purposes the open ended aperture portion 82 may be filled with a lubricant or the plate 80 may be of self-lubricating composition.

The cutter assembly 50 mounts a spring urged card engaging frame 90 (FIG. 14) using the following construction. A supporting frame 92 (FIG. 15) is secured by screws 93 on the cutter plate 62 and a pair of screws 94 passing through the frame 92 and coil compression springs 96 is threaded in the card engaging frame 90 so I that such frame may slide on the outer surfaces of the cutting elements 55-58 during operation of the machine for resiliently clamping the card against the cutter plate 34 just prior to and during the cutting operatlon.

The lever 52 is actuated to move the cutter assembly 50 using the following construction.

Mounted on the frame side plate 11 is an electric motor 101 having mounted thereon a speed reduction unit 102 with the output shaft 104 of this unit extending through frame plate 11, the motor-speed reduction assembly 101, 102 being secured to side plate 11 by bolts 106.

The shaft 104 has secured thereto one end of a shaft 107 as a prolongation of the same, the shaft 107 extending through elongated aligned slotted portions 1 12, 1 13 in a rod 114 and having its other end journalled for rotation in the bearing assembly 109 mounted on frame plate 12; and three cams 110, 111 and 135 are secured on shaft 107 with the cam 111 being located within a longitudinally extending slotted portion 116 of rod 114 for engagement with the spring urged roller 118 which is also in such slotted portion 116 with ends of its shaft 119 being slidably mounted in the aligned rod slots 120 and 121.

The roller 118 is pressed into engagement with cam 111 by a coil compression spring 123 around rod 114 and having one of its ends bearing against a washer 125 with a shouldered portion engaging the roller shaft 1 19, the other end of spring 119 bearing against a washer 127 which is adjustably supported by a nut 128 on rod 114 for adjusting the compression of spring 123.

The other cam 110 spaced from the rod 114 by spacer 130 engages the roller 132 having its shaft 134 secured to rod 114. v v

One end of rod 114 is bifurcated. to straddle an intermediate portion of lever 52 and a pivot pin 136 secured to rod 114 provides a pivot for pivoted movement between rod 1 14 and lever 52. The pivot pin 136 also provides a pivot for an intermediate portion of a pump actuating arm 137 having its lower end cooperable with the movable pump actuating element or piston 62E and its upper end carrying an adjustable screw 142 therein for adjusting the spacing between such screw 143 and the stationary support bracket 23.

It will be seen from this construction that the angular position of cam 110, a cam with two diametrically disposed indented portions 138, 139 (FIG. 7) separated by two diametrically disposed circular lobe portions 140, 141 affects essentially the positioning of lever 52 and hence the positioning of the cutter assembly with respect to the stationary cutter element 34 whereas the angular position of the other cam 111 (FIG. 3) affects essentially the degree of compression of spring 123.

The two cams 110, 111 each being keyed to the same shaft 107 rotate as a unit in the clockwise direction in FIGS. 2, 3, 7, 16 and 17. Considering the effect of angular rotation of shaft 107 between the limits represented by the radial lines 143 and 144 in FIG. 17, corresponding to the region between points A and B on cam 110 and between K and L on cam 111 in FIG. 16. It will be seen that during this angular rotation the cam 110 maintains the cutter assembly in its fully retracted position shown in FIG. 2 but that progressively more energy is stored in the spring 123. At point B, corresponding to point E on cam 1 10 the driving motor is automatically de-energized by means described later so that at point B, a rest position, the spring 123 is fully stressed. When and as the roller 132 leaves point B occasioned by energizing the driving motor (roller 118 now engaging point L on cam 111) and enters the indentation 138, the spring 123 being fully stressed is fully effective-to cause the roller 132 to enter such indentation 138 and to advance the cutter assembly 50 towards the card and in doing so expends energy previously stored in the spring in causing (a) the card engaging frame to be compressed against the card and (b) the card cover sheet aperturing operation. After the cutter assembly is allowed to be advanced in its spring urged guide structure and through the card cover sheet by energy supplied from spring 123 (roller 132 now at the deepest point C in the indentation 138 in cam and roller 118 now engaging the point M on cam 111) further rotation of shaft 107 results in the cam 110 retracting the cutter assembly 50 and the roller 118 sharply dropping from the high part of cam 111 to permit this return movement with minimum energy required by the spring. The driving motor is automatically de-energized when shaft 107 rotates through one half 4) of a revolution when the roller 132 engages the adjacent circular portion E of cam 110 to leave the cam 110 in a position corresponding to that shown in FIG. 17 to await the next cycle of operations which is initiated by manual closure of a switch 200 now described in connection with FIG. 4.

In FIG. 4, the switch 200 is connected in series with the driving motor 101 and is operated in accordance with rotation of the cam on shaft 107, the cam 135 being shown in its normal, at rest, position where one of its two .lobes 135A engages the switch actuating element 200A to thereby maintain switch 200 in its open position. The switch 200 is mounted on a lever plate 202 which has an intermediate portion pivoted at pin 203 on support plate 11, has one of its end pins connected at 205 to one end of lever 207 and has the other one of its ends connected through overcenter snap spring 207 to a pin 209 on support plate 11. The lever 207 has an intermediate portion pivoted on pin 210 on support plate 11 and its other end connected to a transversely extending actuating bar 213 so that by depressing the bar 213 the lever plate 202 is pivoted in a counterclockwise direction in FIG. 4 to cause the spring 207 to snap overcenter to disengage the switch actuating element from cam lobe 135A and to allow the switch 200 to close and thus energize the driving motor causing the cam 135 to rotate in the clockwise direction in FIG. 4. Due to the fact that the overcenter spring 207 now holds the lever plate 202 in its actuated position the adjustable abutment 212 on lever plate 202 is now in the path of movement of the cam lobe 135B which then strikes the abutment 212 to cause the lever plate 202 to rotate clockwise during which the spring 207 travels to its overcenter position shown in FIG. 4 to maintain the switch actuating element 200A in the path of movement of cam lobe 1358 so that when these two last mentioned elements engage the switch 200 is opened to de-energize the motor and stop rotation of shaft 107. Thus only one-half of one revolution of shaft 107 is assured to each manual depression of bar 213.

During this one-half revolution of shaft 107 the air pump is also operated, and also by the energy previously stored in spring 123. Thus during the time that the roller 132 enters the indented portion of cam 110, the lever 52 pivots counterclockwise in FIG. 2 carrying with it the pin 136 upon which the air pump lever 137 is secured by threading it on pin 136 with a washer 136A clamped between it and a shouldered portion of the pin 136 which is thus free to pivot on arm 114. When the upper end of lever 137, more specifically the adjustable screw 142 thereon, engages the stationary bracket 23 the lever 137 pivots in a clockwise direction to cause its lower end to move in engagement with the air pump piston extension 62E to cause an air jet to be produced at nozzle 62A to blow away the rectangular cut out portion of the card cover sheet through the frame aperture 32.

The machine thus using stored energy in a spring to aperture card or card cover sheets assures uniformity of results. Also the cams have long life considering particularly that only the circular portion of cam 110 is fully loaded and pressure on such cam is relieved when the roller 132 engages the indented portion 138 of the cam 110. Of greater significance is the fact that peak power requirements are reduced so that the driving motor may be small and inexpensive, due to low output speed and torque requirements.

While motor operation is preferred it will be appreciated that the cutter may be manually operated using for example a manual operator connected to lever 52 in which case the rod 114 is disconnected from lever 52.

The movable cutter assembly described is particularly useful in each case in progressively cutting that very thin material N which is bonded to that marginal edge portion defining the rectangular apertured portion of card C.

It will be noted that in the present embodiment, double lobe cams are used only to allow the use of very low cost, standard motors. Single or triple lobe carns would provide identical cycling to the device. Further, it can be seen that lever 52 could be rigidly connected to the punch, and operated in circular motion about a lower pivot point.

Also it will be seen that if one inadvertently placed 10 to cards in backwards the punch unit will not drive through the stationary cutting die. The mechanism will go through its cycle, the spring will continue to extend, but will not be able to deliver enough energy to either drive the punch member or damage itself. In other words the spring absorbs this overload. There is no rigid connection such that the mechanism and motor sees the overload and is subject thereto thereby contributing to a safety feature.

In the modified form illustrated in FIGS. 18 through 24 an attempt is made to number the parts therein with the same reference numerals as in the previous figures, raised however by 300 for ease of comparison. It will be seen that there are essentially only three differences namely:

l. in the cutter assembly 350;

2. in the provision of a freely floating card chip remover 401; and

3. in the provision of a pair of rollers 380.

The cutter assembly 350 now comprises a single generally rectangular block as seen in FIG. 21. Such assembly 350 is defined by four raised and pointed corner portions 350B, 350C, 350D and 350E. Each of such corner portions is actually the apex of a forwardly extending triangular portion of the block. The corner portion 350B is at the outer end of the line 350G (FIG. 21) which is the intersection of two face portions 350H, 350]. The corner portion 350C is at the outer end of the line 350L which is the intersection of two face portions 350M, 350N; and the faces 350J, 350M intersect at a line 3501 which is depressed so that in crosssection as seen in FIGS. 20 and 21, the corner portions each extend forwardly as the apex of a solid right angle. The cutter assembly may be characterized as a rectangular block formed with solid triangular portions at each of its corners with the apex of each such triangular portions being in the same plane and extending foremost precisely at each corner. The line 350G representative also of the other three like lines extends diagonally inwardly and downwardly. The line 350P representative also of the other three like lines extends inwardly with all points on such line being substantially at the same elevation. This means that as the assembly 350 is advanced during the cutting operation each of the four corner portions are progressively moved in like measure through the card with cutting or shearing being accomplished progressively at the eight peripheral edge portions, two of which are referenced as 350R and 3508 in FIG. 20 and as will be seen extend towards each other in a downward or inward direction.

As before, there is provided a nozzle 362A (like nozzle 62A) but now a freely floating piston 401 is slidably mounted in the bore of such nozzle as shown in FIGS. 22 and 24. This piston 401 is provided with a series of external grooved portions 401A extending axially thereof to allow the compressed air supplied as before from the pump via hose 362C to escape from the forward end of nozzle 362A. At the same time the pressure of the air causes the piston 401 to move so that ultimately an end of the piston 401 projects through the forward end of nozzle 362A to contact the cut portion of the cover sheet to thereby further assure removal of the cut-out portion from the machine. In other words, the action of the air jet is now supplemented by a mechanical action resulting from movement of the piston 401. During the return stroke of the pump a subatmospheric pressure is developed in hose 362C causing the piston to move backwards to its retracted position from where it again may move with momentum for the above purposes during the succeeding cutting operation. Also, now the cutter assembly 350 is provided with two inwardly disposed raised portions defined by the round heads of rivet-like elements 406, 407 which may be accurately located to provide a'limited contact area with the cut-out portion to again further assure removal of the cut chip.

As seen in FIG. 23 the nozzle 362A is threaded in the cutter block 364 and the cutter assembly 350 is accurately located on block 364 using dowel pins M3. The cutter assembly 350 is otherwise maintained on cutter block 364 and in relationship to the spring urged card engaging frame 390 as previously described in the des'cription of frame 90 in the previous figures.

A pair of rollers 380 rotatably supported on a corresponding pin or shaft 381K now engages the beveled surface 370 of cutter block 364 for generally the same purposes as the previously mentioned plate 80.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

We claim:

1. In apparatus of the character described, a cutter assembly having a support; four cutting knives mounted on said support in a rectangular pattern and with respect to a common plane on said support with each knife having a cutting edge inclined with respect to said plane and with adjacent ends of adjacent knives extending unequal distances from said plane; an apertured plate slidably mounted on said support to a position extending forwardly of and surrounding said knives; and spring means acting between said plate and said support normally urging said plate to said position.

2. Apparatus as set forth in claim 1 in which said support has secured thereto an apertured plate extending around said support; pins slidably mounted on the last mentioned apertured plate and secured to the first mentioned apertured plate; and coil compression springs encircling said pins and comprising said spring means.

3. In apparatus of the character described, a cutter assembly having a support; cutting means mounted on said support in a rectangular pattern and with respect to a common plane on said support with each of said cutting means having at least one cutting edge inclined with respect to said plane; an apertured plate slidably mounted on said support to a position extending forwardly of and surrounding said cutting means; and spring means acting between said plate and said support normally urging said plate to said position, said cutting means comprising cutting knives with each knife having a cutting edge inclined with respect to said plane and with adjacent ends of adjacent knives extending unequal distances from said plane. 

1. In apparatus of the character described, a cutter assembly having a support; four cutting knives mounted on said support in a rectangular pattern and with respect to a common plane on said support with each knife having a cutting edge inclined with respect to said plane and with adjacent ends of adjacent knives extending unequal distances from said plane; an apertured plate slidably mounted on said support to a position extending forwardly of and surrounding said knives; and spring means acting between said plate and said support normally urging said plate to said position.
 2. Apparatus as set forth in claim 1 in which said support has secured thereto an apertured plate extending around said support; pins slidably mounted on the last mentioned apertured plate and secured to the first mentioned apertured plate; and coil compression springs encircling said pins and comprising said spring means.
 3. In apparatus of the character described, a cutter assembly having a support; cutting means mounted on said support in a rectangular pattern and with respect to a common plane on said support with each of said cutting means having at least one cutting edge inclined with respect to said plane; an apertured plate slidably mounted on said support to a position extending forwardly of and surrounding said cutting means; and spring means acting between said plate and said support normally urging said plate to said position, said cutting means comprising cutting knives with each knife having a cutting edge inclined with respect to said plane and with adjacent ends of adjacent knives extending unequal distances from said plane. 